This invention relates to an apparatus for the hot gas corrosion of samples of material and, more specifically, to an apparatus having a pipe for taking up the sample of material, a steam and/or gas source, which is attached to the pipe, and a means for the purpose of evaporating a substance stimulating corrosion.
Turbines are often operated in an atmosphere which stimulates corrosion and which contains, for example, sea salt. When the turbine blades cool down after the turbine has been switched off, the substance stimulating corrosion (e.g., Na.sub.2 SO.sub.4) is deposited on the turbine blades in a concentrated form. When the turbine blades reheat afterwards, the corroding material becomes effective.
In order to examine the corrosive effect of various corroding substances on different samples of material, an apparatus has been developed in the prior art, which apparatus has a horizontal pipe for taking up a sample of material. Steam-saturated air is conducted through the pipe while, at the same time, a substance stimulating corrosion is fed through the pipe wall in a specific concentration. During the course of the experiment, the pipe is heated in a controlled form evenly over its entire length. This known apparatus has the disadvantage that the sample of material to be corroded is arranged lying in the pipe and is, thus, not evenly corroded from all sides. Moreover, the heating-up of the sample of material is coupled with the temperature of the pipe. As the sample of material in the pipe is not arranged concentrically, different areas of the surface of the sample of material have dissimilar temperatures.
The underlying object of the present invention is to provide an apparatus of the kind named by way of introduction, which apparatus makes possible a purposeful and uniform heating and corrosion of the surface of a sample of material and, thus, provides better information about the corrosive behavior of the material.